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Tag Archives: Yu Yang

In the future, gold rushes could occur in sewage plants. Precious metals have been found in large quantity by researchers investigating waste and the passage of nanoparticles (gold, silver, platinum, etc.) into our water. From a Jan. 29, 2015 news article by Adele Peters for Fast Company (Note: Links have been removed),

One unlikely potential source of gold, silver, platinum, and other metals: Sewage sludge. A new study estimates that in a city of a million people, $13 million of metals could be collecting in sewage every year, or $280 per ton of sludge. There’s gold (and silver, copper, and platinum) in them thar poop.

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Funded in part by a grant for “nano-prospecting,” the researchers looked at a huge sample of sewage from cities across the U.S., and then studied several specific waste treatment plants. “Initially we thought gold was at just one or two hotspots, but we find it even in smaller wastewater treatment plants,” says Paul Westerhoff, an engineering professor at Arizona State University, who led the new study.

Some of the metals likely come from a variety of sources—we may ingest tiny particles of silver, for example, when we eat with silverware or when we drink water from pipes that have silver alloys. Medical diagnostic tools often use gold or silver. …

The metallic particles Peters is describing are nanoparticles some of which are naturally occurring as she notes but, increasingly, we are dealing with engineered nanoparticles making their way into the environment.

Engineered or naturally occurring, a shocking quantity of these metallic nanoparticles can be found in our sewage. For example, a waste treatment centre in Japan recorded 1,890 grammes of gold per tonne of ash from incinerated sludge as compared to the 20 – 40 grammes of gold per tonne of ore recovered from one of the world’s top producing gold mines (Miho Yoshikawa’s Jan. 30, 2009 article for Reuters).

While finding it is one thing, extracting it is going to be something else as Paul Westerhoff notes in Peters’ article. For the curious, here’s a link to and a citation for the research paper,

Growing use of nanomaterials in manufactured products is heightening concerns about their potential environmental impact – particularly in water resources.

Tiny amounts of materials such as silver, titanium, silica and platinum are being used in fabrics, clothing, shampoos, toothpastes, tennis racquets and even food products to provide antibacterial protection, self-cleaning capability, food texture and other benefits.

Nanomaterials are also put into industrial polishing agents and catalysts, and are released into the environment when used.

As more of these products are used and disposed of, increasing amounts of the nanomaterials are accumulating in soils, waterways and water-systems facilities. That’s prompting efforts to devise more effective ways of monitoring the movement of the materials and assessing their potential threat to environmental safety and human health.

Three Arizona State University faculty members will lead a research project to help improve methods of gathering accurate information about the fate of the materials and predicting when, where and how they may pose a hazard.

Their “nanoprospecting” endeavor is supported by a recently awarded $300,000 grant from the National Science Foundation.

The first part of this roughly six week food and nano ‘debate’ started off with the May 22, 2014 news item on Nanowerk announcing the Friends of the Earth (FOE) report ‘Way too little: Our Government’s failure to regulate nanomaterials in food and agriculture‘. Adding energy to FOE’s volley was a Mother Jones article written by Tom Philpott which had Dr. Andrew Maynard (Director of the University of Michigan’s Risk Science Center) replying decisively in an article published both on Nanowerk and on the Conversation.

Coincidentally or not, there were a couple of news items about ‘nano and food’ research efforts during the ‘debate’. A June 11, 2014 news item on Nanowerk highlights a Franco-German research project into the effects that nanomaterials have on the liver and the intestines while noting the scope of the task researchers face,

What mode of action do nanomaterials ingested via food have in liver and intestine? Which factors determine their toxicity? Due to the large number of different nanomaterials, it is hardly possible to test every one for its toxic properties. [emphasis mine] For this reason, specific properties for the classification of nanomaterials are to be examined within the scope of the Franco-German research project “SolNanoTox”, which began on 1 March 2014. The [German] Federal Institute for Risk Assessment (BfR) requires data on bioavailability for its assessment work, in particular on whether the solubility of nanomaterials has an influence on uptake and accumulation in certain organs, such as liver and intestine. “We want to find out in our tests whether the criterion ‘soluble or insoluble’ is a determining factor for uptake and toxicity of nanomaterials,” says BfR President Professor Dr. Andreas Hensel.

A risk assessment of nanomaterials is hardly possible at the moment and involves a very high degree of uncertainty, as important toxicological data on their behaviour in tissue and cells are still missing. [emphasis mine] The German-French SolNanoTox research project examines which role the solubility of nanomaterials plays with regard to their accumulation and potential toxic properties. The project is to run for three and a half years during which the BfR will work closely with its French sister organisation ANSES. Other partners are the Institut des Sciences Chimiques de Rennes and Universität Leipzig. The German Research Foundation and French Agence Nationale de la Recherche (ANR) are funding the project.

The tasks of the BfR include in vitro tests (e.g. the investigation of the influence of the human gastrointestinal system) and analysis of biological samples with regard to the possible accumulation of nanomaterials. In addition to this, the BfR uses modern methods of mass spectrometry imaging to find out whether nanoparticles alter the structure of biomolecules, e.g. the structure of the lipids of the cellular membrane. So far, these important tests, which are necessary for assessing possible changes in DNA or cellular structures caused by nanomaterials in food, have not been conducted.

Metallic nanoparticles are to be studied (from the press release),

In the project, two fundamentally different types of nanoparticles are examined as representatives for others of their type: titanium dioxide as representative of water insoluble nanoparticles and aluminium as an example of nanomaterials which show a certain degree of water solubility after oxidation. [emphases mine] It is examined whether the degree of solubility influences the distribution of the nanomaterials in the body and whether soluble materials may possibly accumulate more in other organs than insoluble ones. The object is to establish whether there is a direct toxic effect of insoluble nanomaterials in general after oral uptake due to their small size.

Different innovative analytical methods are combined in the project with the aim to elucidate the behaviour of nanomaterials in tissue and their uptake into the cell. The main focus is on effects which can trigger genotoxic damage and inflammation. At first, the effects of both materials are examined in human cultures of intestinal and liver cells in an artificial environment (in vitro). In the following, it has to be verified by animal experimentation whether the observed effects can also occur in humans. This modus operandi allows to draw conclusions on effects and mode of action of orally ingested nanomaterials with different properties. The goal is to group nanomaterials on the basis of specific properties and to allocate the corresponding toxicological properties to these groups. Motivation for the project is the enormous number of nanomaterials with large differences in physicochemical properties. Toxicological tests cannot be conducted for all materials.

In the meantime, a June 19, 2014 news item on Azonano (also on EurekAlert but dated June 18, 2014) features some research into metallic nanoparticles in dietary supplement drinks,

Robert Reed [University of Arizona] and colleagues note that food and drink manufacturers use nanoparticles in and on their products for many reasons. In packaging, they can provide strength, control how much air gets in and out, and keep unwanted microbes at bay. As additives to food and drinks, they can prevent caking, deliver nutrients and prevent bacterial growth. But as nanoparticles increase in use, so do concerns over their health and environmental effects. Consumers might absorb some of these materials through their skin, and inhale and ingest them. What doesn’t get digested is passed in urine and feces to the sewage system. A handful of initial studies on nanomaterials suggest that they could be harmful, but Reed’s team wanted to take a closer look.

They tested the effects of eight commercial drinks containing nano-size metal or metal-like particles on human intestinal cells in the lab. The drinks changed the normal organization and decreased the number of microvilli, finger-like projections on the cells that help digest food. In humans, if such an effect occurs as the drinks pass through the gastrointestinal tract, these materials could lead to poor digestion or diarrhea, they say. The researchers’ analysis of sewage waste containing these particles suggests that much of the nanomaterials from these products are likely making their way back into surface water, where they could potentially cause health problems for aquatic life.

This piece is interesting for two reasons. First, the researchers don’t claim that metallic nanoparticles cause digestion or diarrhea due to any action in the gastrointestinal tract. They studied the impact that metallic nanoparticles in supplementary drinks had on cells (in vitro testing) from the gastrointestinal tract. Based on what they observed in the laboratory, “… these materials could lead to poor digestion or diarrhea… .” The researchers also suggest a problem could occur as these materials enter surface water in increasing quantities.

With Paul Westerhoff as one of the authors and the reference to metallic nanoparticles entering water supplies, I’m guessing that this research is associated with the LCnano (lifecycle nano) project headquartered at Arizona State university (April 8, 2014 posting).

Getting back to the Franco-German SolNanoTox project, scientists do not know what happens when the cells in your intestines, liver, etc. encounter metallic or other nanoparticles, some of which may be naturally occurring. It should also be noted that we have likely been ingesting metallic nanoparticles for quite some time. After all, anyone who has used silver cutlery has ingested some silver nanoparticles.

There are many, many questions to be asked and answered with regard to nanomaterials in our foods. Here are a few of mine:

How many metallic and other nanoparticles did we ingest before the advent of ‘nanomaterials in food’?

What is the biopersistence of naturally occurring and engineered metallic and other nanoparticles in the body?

What happens as the metallic and other engineered nanoparticles are added to food and drink and eventually enter our water, air, and soil?

Returning to the ‘debate’, a July 11, 2014 article by Sarah Shemkus for a sponsored section in the UK’s Guardian newspaper highlights an initiative taken by an environmental organization, As You Sow, concerning titanium dioxide in Dunkin’ Donuts’ products (Note: A link has been removed),

The activists at environmental nonprofit As You Sow want you to take another look at your breakfast doughnut. The organization recently filed a shareholder resolution asking Dunkin’ Brands, the parent company of Dunkin’ Donuts, to identify products that may contain nanomaterials and to prepare a report assessing the risks of using these substances in foods.

Their resolution received a fair amount of support: at the company’s annual general meeting in May, 18.7% of shareholders, representing $547m in investment, voted for it. Danielle Fugere, As You Sow’s president, claims that it was the first such resolution to ever receive a vote. Though it did not pass, she says that she is encouraged by the support it received.

“That’s a substantial number of votes in favor, especially for a first-time resolution,” she says.

The measure was driven by recent testing sponsored by As You Sow, which found nanoparticles of titanium dioxide in the powdered sugar that coats some of the donut chain’s products. [emphasis mine] An additive widely used to boost whiteness in products from toothpaste to plastic, microscopic titanium dioxide has not been conclusively proven unsafe for human consumption. Then again, As You Sow contends, there also isn’t proof that it is harmless.

“Until a company can demonstrate the use of nanomaterials is safe, we’re asking companies either to not use them or to provide labels,” says Fugere. “It would make more sense to understand these materials before putting them in our food.”

As You Sow is currently having 16 more foods tested. The result should be available later this summer, Fugere says.

I wonder if As You Sow will address the question of whether the nanoscale titanium dioxide they find indicates that nanoscale particles are being deliberately added or whether the particles are the inadvertent consequence of the production process. That said, I find it hard to believe no one in the food industry is using engineered nanoscale additives as they claim (the other strategy is to offer a nonanswer) in Shemkus’ article (Note: Links have been removed).,

In a statement, Dunkin’ Donuts argues that the titanium dioxide identified by As You Sow does not qualify as a nanomaterial according to European Union rules or draft US Food and Drug Administration regulations. The company also points out that there is no agreed-upon standard method for identifying nanoparticles in food.

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In 2008, As You Sow filed nanomaterial labeling resolutions with McDonald’s and Kraft Foods. In response, McDonald’s released a statement declaring that it does not support the use of nanomaterials in its food, packaging or toys. Kraft responded that it would make sure to address health and safety concerns before ever using nanomaterials in its products.

While Shemkus’ article appears in the Guardian’s Food Hub which is sponsored by the Irish Food Board, this article manages to avoid the pitfalls found in Philpott’s nonsponsored article.